Aplicabilidade da técnica de oscilações forçadas modificada na avaliação da impedância respiratória em crianças asmáticas

• Autor(a) principal: Vaccari, Alessandra
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/7753
• topic: Técnica de Oscilações Forçadas; Teste de Função Pulmonar; Impedância Respiratória; Criança; Asma; CIENCIAS DA SAUDE::MEDICINA

Introduction: the prevalence of asthma is increasing worldwide; today it is considered a public health problem; is often underdiagnosed and its severity is also underestimated, greatly increasing morbidity and mortality, especially in the lower socioeconomic and educational classes. In childhood, asthma is the most frequent among chronic diseases and can adversely affect the quality of life of patients and their families. The assessment of lung function may help in the diagnosis and assessment of asthma severity, there are several methods available, however some are inadequate for young children or for people with motor coordination difficulties or cognitive deficits. One method that has a high success rate in situations of poor patient collaboration is the forced oscillation technique (FOT); is a noninvasive procedure that applies airway oscillations through the mouth and measures the impedance of the respiratory system. The real part of the impedance is called the resistance of the respiratory system that reflects the resistance to friction; while the imaginary part is called the reactance of the respiratory system, which reflects the elastic and inertial properties of the lung. Modified FOT measures respiratory mechanics variables, in addition to multi-frequency applications (6 to 32 hertz), checks within breath variables at a 10 hertz monofrequency. Objective: to explore the applicability of FOT in patients with asthma, as a tool for diagnosis and assessment of the severity of obstruction. Methods: observational, cross-sectional study with quantitative approach. The population was composed of subjects from 3 years old to 18 years of age, recruited for convenience from May 2016 to July 2017, at the Pediatric Pulmonology and Pediatrics Service at a school hospital in southern Brazil. The equipment used for the FOT acquisition was built specifically for this study. The measured parameters include impedance, resistance and reactance in the frequencies between 6 to 32 hertz and within-breath variables in the monofrequency of 10 hertz. The analyzes were performed with the Statistical Package for the Social Sciences program with a significance level of 5%. The data were presented in mean and standard deviation or in median and interquartile range, depending on the normal distribution of the variables. For the analysis of the performance of the variables regarding the diagnosis of asthma the individuals were divided into an Asthma group and Control group, formed by healthy individuals from the respiratory point of view from the clinical questionnaire. To analyze the associations of the variables obtained with FOT with the different levels of asthma severity and clinical status, subjects were divided into: controls, mild asthma, moderate asthma and asthma exacerbation. The Spearman rank correlation test was used in the exploratory analysis of lung function data and dichotomous asthma. Comparisons between the Asthma and Control groups were made using the Mann-Whitney test; in the analyzes in which asthma was classified by severity in three levels according to the treatment or clinical state, Kruskal-Wallis was used per stations, not parametric. To examine the ordering of these differences in the different levels of asthma we used the non-parametric Jonckheere-Terpstra trend test. The Receiver Operating Characteristic Curve was used to evaluate the sensitivity, specificity and accuracy of the variables obtained in the pulmonary function test for the correct classification of subjects as controls or asthmatics. The study was approved by the institution's Ethics Committee. Results: 204 subjects were included, after removing the losses, 189 FOT tests with a performance of 95.45% of success in the test were analyzed. For statistical analyzes, the subjects were divided into four groups: healthy controls, mild asthma, moderate asthma and asthma exacerbation. The FOT variables with the highest sensitivity for distinguishing subjects are: X6, X8, ReE-ReI, XeE, XeI, Xmax,E, Xmax,I, Xmean,E and Xmean,I. Conclusions: The study findings indicate that the FOT test has a high success rate and seems to be an adequate method for assessing respiratory impedance in children and adolescents, differentiating subjects with asthma and healthy individuals.